The present disclosure relates to a dynamic imbalanced force generator comprising at least one pair of eccentric mass imbalances and an actuator comprising such a generator.
A dynamic imbalanced force generator comprising a pair of eccentric mass imbalances is known from document FR 2 169 672 (D1).
Also known is a dynamic imbalanced force generator comprising two pairs of eccentric mass imbalances to reduce or even eliminate a vibration generated by a moving body. In this case, the dynamic imbalanced force generator makes it possible to form a variable dynamic imbalanced force generator, also called an actuator. In each pair of imbalances, the two masses of the respective pair rotate in a counter-rotate manner. Implementing two pairs of imbalances then makes it possible to control the amplitude of the delivered dynamic imbalanced force by controlling the phase shift between the two pairs. It is the control of this amplitude, in itself variable, which makes it a real actuator.
An actuator (variable dynamic imbalanced force generator) of this type is described in document U.S. Pat. No. 5,903,077 (D2) in which the eccentric masses are mechanically coupled in pairs. Position sensors are used to achieve the frequency and phase control of these masses. The force generated by the eccentric masses is transmitted via a crankcase supporting the imbalances, which requires that this crankcase has a mass sufficiently large to be sufficiently robust and stiff to be able to transmit the dynamic imbalanced force, and not generate parasitic vibratory modes. Moreover, the mechanical coupling of the counter-rotating eccentric mass imbalances is obtained by external meshing of the two imbalances with parallel axes by means of toothed wheels with a diameter greater than the outside diameter of the imbalances. The volume of the actuator is then greater than the volume of the imbalances themselves, while a large mass not participating in the imbalance effect (the outer toothed ring gear is necessarily balanced and therefore generates no dynamic imbalanced force). Finally, pairs of counter-rotating imbalances are preferably placed one around the other, possibly leading to the introduction of a parasitic vibratory torque into the structure, a torque the amplitude of which is inversely proportional to that of the force generated by the actuator. The actuator thus constituted has a large and non-versatile size.
Another actuator (variable dynamic imbalanced force generator) of this type is described in document EP 2 024 660 (D3). In this document D3, the four eccentric mass imbalances are mechanically independent. This mechanical independence gives freedom in the arrangement of the various imbalances. In particular, in order to reduce the size, the various eccentric masses may be arranged coaxially and side by side. The control of the various imbalances may then be carried out by electronic coupling in order to rotate the imbalances in the desired direction. However, as illustrated in FIG. 19a, this coaxial side-by-side position generates a parasitic torque Mp that is linked to the existence of a non-zero distance along the common axis between the points of application of the forces F1 (the first imbalance of a pair when it rotates) and F2 (the second imbalance of this same pair when it rotates).
Yet another actuator (generator of variable dynamic imbalanced forces) of this type is proposed in document EP 0 409 462 (D4). Here, the four imbalances are also mechanically independent. In order to prevent a parasitic torque from being generated, the imbalances are nested, i.e. the different centers of gravity of each imbalance lie in the same plane, which, in this case, is perpendicular to the coaxial axis of rotation of the various imbalances. On the other hand, its overall size is generally greater than that which is implied by the coaxial and side-by-side arrangement of the various imbalances of document D3. In fact, the overall size is affected by the radial size associated with this nesting and also by the integration of the motors dedicated to each imbalance and located between two imbalances.
The present invention aims to solve at least one of the aforementioned disadvantages.